The present invention relates to a latch assembly and, more particularly, to a latch assembly for a double door, providing an automatic locking function while closing a follower door of the double door.
A double door generally includes a primary door and a follower door pivotably mounted to two vertical beams of a door frame. A lock is mounted to the primary door and includes a handle on a side of the primary door and a first latch on an end face of the primary door. The first latch can be retracted into the primary door upon pivotal movement of the handle. Upper and lower latch assemblies are mounted to upper and lower ends of the follower door. The upper latch assembly includes an actuation latch extending beyond an end face of the follower door and a second latch normally extending beyond an upper face of the follower door. The lower latch assembly includes an actuation latch extending beyond the end face of the follower door and a third latch normally extending beyond a bottom face of the follower door. When the follower door is moving from an open position to a closed position, each of the second and third latches is moved from an extended, latching position to a retracted, unlatching position. When the follower door is in the closed position, the second latch is engaged in a groove in the door frame, and the third latch is engaged in a groove in the ground, locking the follower door. Since the first latch of the lock on the primary door is engaged with a receptacle in the follower door, the primary door can not be opened, either. Thus, the double door can be reliably locked. However, if the primary door is closed while the follower door is not completely closed (namely, the second latch is not aligned with the groove in the door frame, and the third latch is not aligned with the groove in the ground), the second and third latches can not be moved to the exact latching positions, leading to damage to the upper and lower latch assemblies. Furthermore, the first, second, and third latches may be deformed by the heat during a fire and, thus, moved to the unlatching position, leading to the risks of opening of the double door and spread of the fire.
Thus, a need exists for a latch assembly providing an automatic locking function for a double door.